Calculation of Mutual Information for Partially Coherent Gaussian Channels With Applications to Fiber Optics

Abstract

The mutual information between a complex-valued channel input and its complex-valued output is decomposed into four parts based on polar coordinates: an amplitude term, a phase term, and two mixed terms. Numerical results for the additive white Gaussian noise (AWGN) channel with various inputs show that, at high signal-to-noise ratio (SNR), the amplitude and phase terms dominate the mixed terms. For the AWGN channel with a Gaussian input, analytical expressions are derived for high SNR. The decomposition method is applied to partially coherent channels and a property of such channels called “spectral loss” is developed. Spectral loss occurs in nonlinear fiber-optic channels and it may be one effect that needs to be taken into account to explain the behavior of the capacity of nonlinear fiber-optic channels.

DOI: 10.1109/TIT.2011.2162187

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Cite this paper

@article{Goebel2011CalculationOM, title={Calculation of Mutual Information for Partially Coherent Gaussian Channels With Applications to Fiber Optics}, author={Bernhard Goebel and Ren{\'e}-Jean Essiambre and Gerhard Kramer and Peter J. Winzer and Norbert Hanik}, journal={IEEE Transactions on Information Theory}, year={2011}, volume={57}, pages={5720-5736} }